Variation of Digit Ratio (2D: 4D) in Schizophrenic and Non-schizophrenic Individuals

The primary etio-pathological model for schizophrenia is the neuro-developmental hypothesis. Present study was conducted at NIMHANS with the objective to compare the digit ratio (2D:4D) in schizophrenia cases and non-schizophrenia controls. Sixty schizophrenia patients and sixty subjects with no psychosis were assessed by clinical diagnostic interview by principal investigator and the diagnosis was confirmed by another psychiatrist. They were included in the study after the inclusion and exclusion criteria were met and the 2D:4D was measured in both the hands in both cases and controls using transparency method. Continuous variable (2D:4D) was analyzed using independent T test. The comparison of digit ratio in cases and controls showed that the 2D:4D ratio was higher in schizophrenic patients compared to non-schizophrenic controls but it was significant only in left hand. The comparison within subgroups showed that the 2D:4D was higher in schizophrenic males and females but it was statistically significant only on left side. Among normal controls, the digit ratio was less in males (more in females), but the difference was not statistically significant. The right digit ratio is higher in schizophrenic males whereas on left side it is higher in female schizophrenics but both of them have not reached statistical significance.